Robert the rebuilder settles in

Celtic's fans are appreciating their goalkeeper at last. Phil Gordon speaks to him

Robert Douglas always knew he would earn his living with his hands. Yet the man who was on a building site barely five years ago could never have suspected they would take him to Spain.

On Thursday night, in the Mestella stadium, Douglas finally cemented his relationship with Celtic's dubious supporters. The goalkeeper threw up a formidable barrier which it took Valencia 70 minutes to breach – a repeat against Rangers today will have him in with the bricks at Parkhead.

Though Martin O'Neill had faith in the man he bought from Dundee for £1.25 million in October 2000, it has taken Douglas a year to win over the fans. It didn't help that his Old Firm debut saw the towering keeper pick the ball out of the net five times.

Douglas could have allowed the 5-1 defeat last November to haunt him. Instead, he has built upon shaky foundations to establish himself not just as Celtic's No 1, but possibly Scotland's too if he maintains the form which defied Valencia in the Uefa Cup tie.

Craig Brown, who watched in admiration as Douglas frustrated the Spanish side, remarked that his successor as Scotland manager will inherit a rival to Neil Sullivan. It was in stark contrast to the series of gaffes which pockmarked Douglas's early days at Parkhead last season.

Ironically, the Scotland squad keeper – he has yet to win a cap – was also courted by his rivals in today's Glasgow derby. "I have followed him for a long time," said the Rangers manager Dick Advocaat, "but I could not offer him the guarantees of first-choice." O'Neill could, installing Douglas ahead of Jonathan Gould – then No 2 to Sullivan with Scotland – and Dimitri Kharin.

Douglas's doubts in his rapid elevation manifested themselves into errors on the pitch, none more so than that ignominious day at Ibrox. Even though Celtic won the treble, many said it was in spite of their goalkeeper rather than because of him.

Douglas sought out O'Neill during the summer for reassurance. "Everything happened so quickly to me," Douglas said. "Eight years ago I was an amateur and was working as a builder. I spoke to the manager during pre-season and he backed me 100 per cent. It gave me confidence and I hope I can repay him."

However, it has been in Europe that Douglas has put in the most impressive work in building his reputation. Agile reactions against FC Porto and Rosenborg in the Champions' League were followed by a commanding performance against Juventus and then that show in Valencia.

Yet, Douglas has not grown too big for his working boots. Reflecting that his Juventus counterpart, Gianluigi Buffon, the world's most expensive keeper, was also having a hard time from critics in Italy, Douglas smiled and said: "£33m is a lot for a keeper – but can he build houses?"

O'Neill detects the growth in his keeper's self-esteem. "Much was made of the Rangers game last season when Robert lost five goals and bore more criticism than the rest of the team. While he was not best pleased, it should not have been the end of the world.

"I never thought for one minute of not sticking by him and since that time we've hardly lost a league game. His problem was in adjusting. Not just adjusting to a big, big club but also games here when he had been normally used to being busy.

"At Dundee, there would not have been a spell when he would have gone five minutes without being in the game whereas here you can go 20 minutes without touching it.

"It's concentration as much as anything else. I believe goalkeepers actually thrive on plenty of action and in Valencia he made a good save early and that set him up for the siege I fully expected from a team who were only a penalty away from winning the Champions' League."

However, O'Neill will dispel any European hangover from his players before today's high-noon showdown. "Rangers is a totally different game altogether and if you go in with that attitude you would get beaten."